Browsing by Author "Caetano, Liliana Aranha"
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- Alginate-chitosan particulate delivery systems for mucosal immunization against tuberculosisPublication . Caetano, Liliana Aranha; Figueiredo, Lara; Almeida, António J.; Gonçalves, Lídia M. D.Although vaccination is still the most cost-effective strategy for tuberculosis control, there is an urgent need for an improved vaccine. Current BCG vaccine lacks efficacy in preventing adult pulmonary tuberculosis, the most prevalent form of the disease. Targeting nasal mucosa, Mycobacterium tuberculosis infection site, will allow a simpler, less prone to risk of infection and more effective immunization against disease. Due to its biodegradable, immunogenic and mucoadhesive properties, chitosan particulate delivery systems can act both as carrier and as adjuvant, improving the elicited immune response. In this study, BCG was encapsulated in alginate and chitosan microparticles, via a mild ionotropic gelation procedure with sodium tripolyphosphate as a counterion. The particulate system developed shows effective modulation of BCG surface physicochemical properties, suitable for mucosal immunization. Intracellular uptake was confirmed by effective transfection of human macrophage cell lines.
- Analysis of Aspergillus spp. burden by culture based-methods and molecular methods in different occupational environments: what needs to be done?Publication . Gomes, Anita Quintal; Faria, Tiago; Caetano, Liliana Aranha; Sabino, Raquel; Viegas, CarlaAim of the study - Fungal burden has traditionally been detected by conventional culture analysis, which despite its limitations, is widely used by the scientific community. Alternatively, quantitative real-time PCR (qPCR), based on the amplification of genomic regions specific to certain fungal species, has been associated with increased sensivity, allowing the detection of dormant forms of fungi, such as spores. We present several studies where both methods were used to detect the presence of toxigenic fungi, namely Aspergillus, particularly from the Fumigatus Flavi and Circumdati sections.
- Analysis of fungal burden by conventional and molecular methods in different settings and matrices: implications for public and occupational healthPublication . Gomes, Anita Quintal; Faria, Tiago; Caetano, Liliana Aranha; Carolino, Elisabete; Viegas, Susana; Viegas, CarlaFungal burden has traditionally been detected by conventional culture analysis. This method allows the identification and quantification of organisms posing high health/occupational risk and is widely used by the scientific community. The fungal burden determined by culture analysis can, in most studies, be compared with legal and scientific guidelines allowing an estimation of the degree of severity of the exposure. However, this method is limited by several factors, including incubation conditions such as the incubation time, which can be very long for some species, thus preventing a quick assessment of fungal burden. Another limiting factor is competition between species: clinically relevant species might possess lower growth rates than other non-toxic fast growing fungi thus hampering their detection. These limitations can be overcome by the use of quantitative real-time PCR (qPCR). This method, based on the amplification of genomic regions specific to certain fungal species, increases sensitivity, allowing the specific detection of a given species and removing interference by other species present in the sample. qPCR also allows the detection of dormant forms of fungi, such as spores. Thus the ideal scenario is to use these the two methods in parallel, as they complement each other to provide useful information for the assessment of exposure to fungi. We briefly describe several studies where both methods were used to detect the presence of toxigenic fungi, namely Aspergillus, particularly from the Fumigati, Flavi and Circumdati sections. These include fungal analysis from different matrices such as air, feed and coffee and within different settings, including wastewater treatment plants, slaughterhouses, feed industries, poultry and swine pavilions. The results obtained with both conventional and molecular methods are compared and discussed as well as its implications for the exposed workers' health.
- Antioxidant activity and cytotoxicity of solubilized C60 and its conjugates with butylated hydroxytoluenePublication . Nunes, A. S.; Matias, A.; Caetano, Liliana Aranha; Graça, Anabela; Simplício, Ana LuísaIt has been described that fullerenes (C60) present interesting properties with potential application in clinical conditions related to oxidative stress. One of the most prominent features of fullerenes is the ability to quench free radicals. However, because of its poor solubility, this has been studied mostly in organic solutions, while the antioxidant activity and cytotoxicity of fullerenes and their derivates in aqueous medium is not well characterized. The antioxidant capacity of synthesised C60-conjugates has been investigated and its was higher comparing to C60 isolated. The aim of this study was to assess the viability of C60-conjugates by determining its antioxidant activity and cytotoxicity in bio-relevant media.
- Approaches to tuberculosis mucosal vaccine development using nanoparticles and microparticles: a reviewPublication . Caetano, Liliana Aranha; Almeida, António José; Gonçalves, Lídia Maria DiogoNext-generation vaccines for tuberculosis should be designed to prevent the infection and to achieve sterile eradication of Mycobacterium tuberculosis. Mucosal vaccination is a needle-free vaccine strategy that provides protective immunity against pathogenic bacteria and viruses in both mucosal and systemic compartments, being a promising alternative to current tuberculosis vaccines. Micro and nanoparticles have shown great potential as delivery systems for mucosal vaccines. In this review, the immunological principles underlying mucosal vaccine development will be discussed, and the application of mucosal adjuvants and delivery systems to the enhancement of protective immune responses at mucosal surfaces will be reviewed, in particular those envisioned for oral and nasal routes of administration. An overview of the essential vaccine candidates for tuberculosis in clinical trials will be provided, with special emphasis on the potential different antigens and immunization regimens.
- Are in vitro cytotoxicity assessments of environmental samples useful for characterizing the risk of exposure to multiple contaminants at the workplace? A systematic reviewPublication . Viegas, Carla; Pena, Pedro; Gomes, Bianca; Dias, Marta; Caetano, Liliana Aranha; Viegas, SusanaIn some occupational environments, risk characterization is challenging or impossible to achieve due to the presence of multiple pollutants and contaminants. Thus, in vitro testing using the most relevant cell lines will provide information concerning health effects due to the co-exposure to multiple stressors. The aim of this review article is to identify studies where the cytotoxicity assessment was performed in environmental samples, as well as to describe the main outputs and challenges regarding risk characterization and management. This study is based on a study of the available information/data on cytotoxicity assessment performed on environmental samples following the PRISMA methodology. Different cell lines were used depending on the environment assessed and exposure routes implicated. The A549 alveolar epithelial cell line was applied in four studies for occupational exposure in the waste sorting industry and for outdoor environments; lymphocytes were used in two studies for occupational and outdoor environments; swine kidney cells were used in three studies performed in the waste industry and hepatocellular/Hep G2 in one study in the waste industry. Cytotoxicity assessments in environmental samples should have a more prominent role due to their contribution to identifying and better understanding the associations between co-exposure to environmental contaminants and adverse human health effects as a prioritization for risk management.
- Are we neglecting the importance of azole resistance screening in indoor air quality assessments?Publication . Viegas, Carla; Almeida, Beatriz; Gomes, Bianca; Dias, Marta; Cervantes, Renata; Caetano, Liliana AranhaIntroduction: The microbial exposure, as well as their metabolic products, has been frequently reported as a high risk of respiratory effects and general health hazards. Regarding the Portuguese legislation for IAQ, the microbial assessment covers only air sampling and culture-based methods (malt extract agar as only culture media to be applied). Fungal legal criteria consist of a fungal load ratio between indoor and outdoor, which should be lower than 1 (I/O<1). Purpose: Analyze the importance of including the characterization of the azole resistance profile in indoor air quality assessments.
- Aspergillus distribution on waste collection trucksPublication . Dias, Marta; Pena, Pedro; Cervantes, Renata; Gomes, Bianca; Caetano, Liliana Aranha; Viegas, CarlaIntroduction: While better waste management is viewed as a critical contributor to reducing health outcomes and harmful environmental impacts, microbiological occupational exposure in the waste management industry is often overlooked, resulting in detrimental health effects on employees. Some waste workers, such as garbage collectors and truck drivers transporting the residential waste, spend part of their shift in a truck cabin and part of it in a workplace where organic materials are processed. The aim of this study was to investigate the Aspergillus spp. contamination present in 32 waste collection trucks (WCT).
- Aspergillus prevalence in air conditioning filters from vehicles: taxis for patient transportation, forklifts, and personal vehiclesPublication . Viegas, Carla; Moreira, Ricardo; Faria, Tiago; Caetano, Liliana Aranha; Carolino, Elisabete; Gomes, Anita Quintal; Viegas, SusanaThe frequency and importance of Aspergillus infections is increasing worldwide. This study aimed to assess the occupational exposure of forklifts and taxi drivers to Aspergillus spp. Nineteen filters from air conditioning system of taxis, 17 from forklifts and 37 from personal vehicles were assessed. Filters extract were streaked onto MEA, DG18 and in azole-supplemented media. Real-time quantitative PCR amplification of selected Aspergillus species-complex was also performed. Forklifts filter samples presented higher median values. Aspergillus section Nigri was the most observed in forklifts filters in MEA (28.2%) and in azole-supplemented media. DNA from Aspergillus sections Fumigati and Versicolores was successfully amplified by qPCR. This study enlightens the added value of using filters from the air conditioning system to assess Aspergillus spp. occupational exposure. Aspergillus azole resistance screening should be included in future occupational exposure assessments.
- Aspergillus section Fumigati in firefighter headquartersPublication . Viegas, Carla; Gomes, Bianca; Dias, Marta; Carolino, Elisabete; Caetano, Liliana AranhaBackground: Aspergillus section Fumigati is one of the Aspergillus sections more frequently related to respiratory symptoms and by other health outcomes. This study aimed to characterize Aspergillus section Fumigati distribution in eleven firefighter headquarters (FFHs) to obtain an accurate occupational exposure assessment. Methods: A sampling approach protocol was performed using active (impaction method) and passive sampling methods (floor surfaces swabs, electrostatic dust collectors (EDCs), and settled dust). All samples were analyzed by culture-based methods and passive sampling was used for molecular detection of Aspergillus section Fumigati. Results: Of all the matrices, the highest counts of Aspergillus sp. were obtained on settled dust filters (3.37% malt extract agar—MEA, 19.09% dichloran glycerol—DG18) followed by cleaning cloths (1.67% MEA; 7.07% DG18). Among the Aspergillus genus, the Fumigati section was predominant in Millipore and EDC samples in MEA (79.77% and 28.57%, respectively), and in swabs and settled dust filters in DG18 (44.76% and 30%, respectively). The Fumigati section was detected more frequently in DG18 (33.01%) compared to MEA (0.33%). The Fumigati section was observed in azole supplemented media (itraconazole and voriconazole) in several passive sampling methods employed and detected by qPCR in almost all passive samples, with EDCs being the matrix with the highest prevalence (n = 61; 67.8%). Conclusion: This study confirms that Aspergillus sp. is widespread and the Fumigati section is present in all FFHs. The presence of fungi potentially resistant to azoles in the FFHs was also observed. Further studies are needed to identify the best corrective and preventive measures to avoid this section contamination in this specific occupational environment.